The field of art to which the invention pertains includes the art of air and fuel carburetion systems for internal combustion engines and to fuel introduction or metering means for such systems. Patents disclosing and claiming such apparatus are generally classified in Patent Office Classes 239 and 261.
In the past, it has generally been considered either undesirable or impractical to form and maintain a well atomized and distributed mixture of liquid fuel droplets and air for introduction into the intake manifold and thence to the cylinders or other combustion chambers of an internal combustion engine.
Fuel atomizing devices of the type disclosed in CR-1 are required to operate over an extremely wide range of both air and fuel introduction rates when used in an automobile. Air and fuel introduction rates may increase by a factor of as much as 40 in comparing idling conditions with those encountered during rapid acceleration. Successful operation of such devices in the supplying of a uniform dispersion of fuel droplets in air to the cylinders of an engine requires distribution of the fuel in the air stream in a uniform manner. While this can be attained using conventional spray nozzles within relatively narrow ranges of air and fuel flow rates, only apparatus having special characteristics provides uniform fuel introduction where the "turn-down" ratio of both the air and fuel flow rates is as large as it is in devices of the type disclosed in CR-1. These characteristics include the ability to maintain streamline flow of the air over a wide range of flow rates and the avoidance of the formation of fuel droplets of too large a size at the point at which the liquid fuel enters the air stream thus, in turn, effecting uniform distribution of fuel into the air stream. It is also desirable that the ratio of the cross-sectional areas of the inlets of the air flow passages wherein flow acceleration takes place to the cross-sectional area at point of maximum constriction fall within certain limits.
Researchers in the field of liquid atomization have determined that certain characteristics are highly desirable for the production of liquid fuel-air mixtures suitable for combustion. These include:
1. The paralleling of the flow of air and liquid to be atomized. PA1 2. The uniform introduction of the liquid to be atomized into the atomizing air stream.